private void DanhSachThongKe()
        {
            int            i      = 0;
            List <ThongKe> tklist = tkbll.ThongKePhieuXuat();

            dgvThongKePhieuXuat.Rows.Clear();
            foreach (ThongKe tks in tklist)
            {
                DataGridViewRow row = new DataGridViewRow();
                row.CreateCells(dgvThongKePhieuXuat);
                row.Cells[0].Value = i + 1;
                row.Cells[1].Value = tks.MaSp.ToString();
                row.Cells[2].Value = tks.TenSp.ToString();
                row.Cells[3].Value = tks.TenLoai.ToString();
                row.Cells[4].Value = tks.TenSx.ToString();
                row.Cells[5].Value = tks.TenKh.ToString();
                row.Cells[6].Value = tks.Slx.ToString();
                row.Cells[7].Value = tks.TongTien;
                row.Cells[8].Value = tks.PhanTram.ToString();
                row.Cells[9].Value = tks.ThanhTien;

                dgvThongKePhieuXuat.Rows.Add(row);
                ++i;
            }
            cboTongPhieuXuat.Text = i.ToString();
        }